Search Results (3,969)

This work develops an analytical framework for nonlinear fractional partial differential equations that combine Kirchhoff-type terms, double-phase operators, and $\psi$-Hilfer fractional derivatives. This paper investigates two classes of problems involving variable-exponent growth conditions. The first problem analyzes general nonlinear sources and formulates the solution as a fixed point of a nonlinear operator. Precisely, by proving that the functional energy is coercive, hemicontinuous, and strictly monotone, we establish the existence and the uniqueness of weak solutions via monotone operator theory. The second problem incorporates a convection-type nonlinearity, which breaks variational structure and requires the more robust theory of pseudomonotone operators. Under suitable growth and mixed-order assumptions on the nonlinearity, we prove the existence of at least one weak solution. The main tools are grounded in variable-exponent Lebesgue and Musielak–Orlicz–Sobolev spaces, with compact embeddings, modular estimates, and fractional integral identities playing a key role in the proofs. We note that the results contribute to the mathematical modeling of phenomena involving nonlocal elasticity, viscoelastic materials, phase-transition media, and fractional dynamical systems where the stiffness of the medium depends on the total deformation (Kirchhoff effect) and the energy density alternates between distinct growth regimes (double-phase). The $\psi$-Hilfer derivative enhances the scope by enabling models with tunable memory and hereditary effects. Full article

Background and Objectives: Cardiovascular disease (CVD) is the leading cause of death globally. The World Health Organization has called for investigations into traditional systems of medicine for CVD prevention. Ayurveda includes a classical herbal formulation called Maharishi Amrit Kalash (MAK) traditionally used for disease prevention, health promotion and healthy aging. The study objective was to evaluate MAK effects on biomarkers of vascular function and structure compared to vitamin C and E supplementation in a high CVD risk population. Materials and Methods: In this double-blind randomized controlled trial, 138 Black men and women (mean age 65 ± 7 years) with established CVD or high CVD risk were assigned to either MAK (n = 46), vitamin C/E (n = 46), or placebo (n = 46) for 12 months. The primary outcomes were change in brachial artery reactivity testing (BART) with flow-mediated dilation (FMD, endothelium-dependent) and nitroglycerin-mediated dilation (NMD, endothelium-independent). Other outcomes included carotid intima-media thickness (cIMT), blood pressure, and serum lipids. ANCOVA and pairwise comparisons were performed. Results: After 12 months of intervention, the MAK group demonstrated significant improvement in BART-NMD compared to placebo (mean change + 4.18% vs. +2.95%, p = 0.018) and numerical but non-significant improvement compared to the +3.32% mean change for the Vitamin C/E group (p = NS). There were no significant group differences for BART-FMD, cIMT, blood pressure, and lipids. Intervention compliance ranged from 70–80%. Conclusions: In this randomized controlled trial, 12 months of MAK supplementation improved endothelium-independent vascular smooth muscle function (BART-NMD) in Black adults at high CVD risk. The MAK group achieved a mean BART-NMD of approximately 15.6%, reaching the established threshold for normal vascular smooth muscle function. This selective improvement in smooth muscle responsiveness without changes in endothelial function, vascular structure, or conventional risk factors suggests MAK may influence specific pathways relevant to vascular aging. Larger studies with clinical outcomes are needed to further evaluate this effect on cardiovascular health in aging and high-risk populations. Full article

The oxygen evolution reaction (OER) constitutes a critical bottleneck in water electrolysis for hydrogen production owing to its sluggish four-electron transfer kinetics. Double perovskite oxides (A₂BB’O₆) have emerged as exceptional OER catalysts distinguished by their stable crystal frameworks and flexible active-site tunability. Crucially, the alternating ordering of B and B’ cations at octahedral positions creates a unique lattice enriched with oxygen vacancies. Leveraging these intrinsic structural advantages, we synthesized a porous Ru-doped double perovskite oxide Sr₂Fe_1.9Ru_0.1O_6-δ (SFRO-850) featuring increased oxygen vacancies via a sol–gel route. Electrochemical measurement shows that SFRO-850 exhibits outstanding OER activity with a low overpotential of 326 mV at a current density of 10 mA cm⁻² and a Tafel slope of 67.48 mV dec⁻¹, superior to the undoped material and its counterparts. The results validate the efficacy of the double perovskite framework as a superior platform for hosting catalytically active sites, offering a viable pathway toward high-performance, low-noble-metal-content OER catalysts. Full article

The reliable joining of ultra-thick aluminum alloy plates remains a critical technical challenge in modern industrial manufacturing, often hindered by defects such as porosity and excessive distortion associated with conventional fusion welding. The novelty of this work lies in the characterization of the intermediate layer overlapping zone in 110 mm ultra-thick plates, which has rarely been reported. The motivation is to overcome the limitations of single-pass FSW for thick plates, such as insufficient material flow and high tool forces, by adopting a sequential double-sided strategy. Furthermore, this technique may help moderate the through-thickness heat input variation, although no direct thermal measurements were made. The weld nugget zone consists of uniformly fine, recrystallized α-Al grains. In contrast, the heat-affected zone displays distinctly laminar grain structures. The overlapping regions within the intermediate layer, which undergo two thermal cycles, exhibit refined grain sizes. A well-defined interface is evident between the advancing-side weld nugget zone and the thermo-mechanically affected zone. The overall tensile strength of the FSW joint is approximately 81% of the base material, and the tensile specimen fractured at the interface between the thermo-mechanically affected zone and the heat-affected zone. Along the thickness of the weld joint, a “W”-shaped microhardness distribution is observed at the surface and subsurface, whereas the intermediate layer exhibits a distinct “V”-shaped profile. The lowest microhardness value is located in the intermediate layer overlapping area due to the insufficient heat input and limited grain growth in this region. In summary, under the specific welding parameters tested (130 rpm, 15 mm/min, 110 mm thick), double-sided friction stir welding produces defect-free joints in AA 5052-H32, suggesting its potential for thick-plate applications, offering a practical and effective solution for manufacturing high-performance aluminum alloy structures. Potential industrial applications include pressure vessels for chemical storage, ship hull structures, and heavy-duty transportation components where ultra-thick aluminum plates are required. Full article

The reinforced concrete structures of many bridges and buildings in Taiwan are over 30 years old. Seismic retrofitting of these structures requires an accurate assessment of reinforcement configuration and corrosion conditions to ensure structural safety and seismic performance. In this study, a 1 GHz ground-penetrating radar (GPR) antenna was used to scan reflected signals from single- and double-row reinforcing bars embedded in concrete. Based on established principles reported in previous studies, detailed analyses were conducted, including the use of the approximate circumference method to estimate reinforcing bar dimensions and the determination of spacing between double-row reinforcing bars (6–8 cm). The synthetic aperture focusing technique was first applied to process the original GPR data matrix. Subsequently, physical parameters related to interface diffraction, such as the perimeter S of the reinforcing bar, were extracted using the dielectric constant of the material interface, the calculated power reflection coefficient, and the First Fresnel Zone. These approaches enabled more accurate estimation of reinforcing bar dimensions (e.g., equivalent to #3 bar size) and improved resolution of spacing between double-row reinforcing bars to 3–6 cm. The results demonstrate that using the synthetic aperture focusing technique to process GPR data enhances the ability to determine reinforcing bar dimensions, interpret bar spacing, and improve imaging resolution, thereby providing a reliable reference for the safety assessment of reinforced concrete structures. Full article

Radioactive Ba²⁺ poses significant risks to nuclear safety and environmental protection, yet its efficient removal from nuclear wastewater remains a considerable challenge. Herein, Mg-Al layered double hydroxides (LDHs) were synthesized via a co-precipitation method and systematically optimized by tuning the Mg/Al molar ratio and calcination temperature. The optimal material, obtained by calcining Mg-Al LDH with a Mg/Al ratio of 4:1 at 450 °C (denoted as HT-450), exhibited a high apparent Ba²⁺ uptake capacity of 416 mg g⁻¹ and reached equilibrium within 15 min. Structural and spectroscopic analyses indicate that Ba²⁺ immobilization is more appropriately described as a reconstruction-coupled, interfacially mediated mineralization process, in which insoluble BaCO₃ forms in close association with the reconstructed HT-450 surface rather than through simple reversible adsorption or ion exchange. HT-450 also exhibited stable performance over a wide pH range of 3–7, high selectivity toward Ba²⁺ in the presence of competing mono-, di-, and trivalent cations, and excellent radiation tolerance, retaining approximately 95% of its initial uptake capacity after exposure to 200 kGy high-energy electron irradiation. These results demonstrate that HT-450 is a promising candidate for the rapid and stable immobilization of Ba²⁺ from Ba-containing radioactive wastewater. Full article

Real-world autonomous agents learn under nonstationarity, safety constraints, and finite energetic budgets. We develop a framework for perennial learning—agents that continuously refine their models while provably controlling the cost of forgetting—by unifying three classical pillars: Kolmogorov complexity, which equates scientific discovery with algorithmic compression; Landauer's principle, which assigns a minimal thermodynamic cost of k_BT ln 2 per erased bit to every irreversible model update; and port-Hamiltonian (PH) dynamics, whose (J − R)∇H decomposition separates zero-cost reversible inference from costly irreversible forgetting by construction. The Maxwell demon analogy is formalized: each learning episode is a Szilard cycle in which information acquisition, belief transport, and memory erasure must balance thermodynamically. The information-distance framework, comprising the normalized information distance (NID) and normalized compression distance (NCD), provides a computable geometry for measuring learning progress and guiding curriculum design. We separate the ideal  uncomputable regularizer based on prefix complexity from the  practical  compressor/MDL (minimum description length) surrogate that appears in optimization and prove a calibration lemma linking the two under a mild uniform-accuracy assumption. Under explicit regularity, compact-sublevel, and non-energy-extracting assumptions, we prove a passivity speed limit for curriculum-induced contractions of the effective feasible set. Under local asymptotic normality, we reprove that Fisher information is a   local  posterior codelength proxy rather than an exact theorem about algorithmic entropy. A conditional sequential information-budget proposition shows that the per-stage sample requirement scales as \(\widetilde{O}(\Delta k_t/\lambda_\star)\), where \(\Delta k_t\) is the {number of materially changed model coordinates} (not the total model complexity \(k_t\)); the \(k^3\to\Delta k\) improvement is conditional on a warm-start assumption and a chosen cold-start baseline. A double-integrator running example with a moving obstacle illustrates the architecture. Full article

Introduction: Orthobiologics such as Platelet-Rich Plasma (PRP) and Injectable Platelet-Rich Fibrin (i-PRF) have emerged as promising tools in regenerative medicine. However, the lack of methodological standardization and the still limited comparative characterization between these products represent significant barriers to their optimized clinical application. This comparative laboratory study aimed to characterize and differentiate PRP and i-PRF, focusing on their cellular composition, obtained volume, and total Platelet-Derived Growth Factor (PDGF-BB) content. Materials and Methods: This study was conducted with 34 individuals meeting standard blood donation criteria. Peripheral blood samples were collected from all participants. PRP was obtained using a modified double-spin centrifugation protocol, whereas i-PRF was prepared using a modified low-speed centrifugation technique. Cellularity (platelet and leukocyte counts), final produced volume, and total PDGF-BB content were assessed using complete blood count analysis and an enzyme-linked immunosorbent assay (ELISA), respectively. Statistical analysis was performed using Linear Mixed Models (LMMs). Results: Both protocols resulted in significant increases in platelet and leukocyte concentrations compared to baseline values. PRP showed significantly higher platelet and leukocyte concentrations compared with i-PRF, as well as markedly higher PDGF-BB levels. In contrast, i-PRF yielded a substantially greater final volume and enabled a higher absolute delivery of total leukocytes, whereas PRP delivered a greater absolute number of platelets. In exploratory analyses, female sex, the presence of comorbidities, and increased abdominal circumference were associated with variations in product volume and cellular composition. Discussion: These findings indicate that PRP and i-PRF exhibit distinct biological profiles in terms of cellularity, volume, and total PDGF-BB content. Whether these laboratory differences translate into distinct clinical outcomes remains unknown. The results should therefore be viewed as hypothesis-generating: they suggest that PRP and i-PRF may not be interchangeable, and that future randomized clinical trials are needed to define product-specific indications based on the target tissue and desired biological mechanism. Full article

Halide double perovskite materials have been used for various applications; their bandgap (E_g) and heat of formation (ΔH_f) are their key properties. They can be obtained through calculations based on high-throughput density functional theory (DFT), but such calculations are computationally expensive and time-consuming. Machine learning (ML) has proved to be an effective tool for screening potential materials. The prediction accuracy of ML models strongly depends on both input features and ML algorithms. However, there is no unified feature set with which ML models can effectively distinguish halide double perovskite materials. Although it has been proven that stacking ML models can achieve higher prediction accuracy than individual ML models, little attention has been paid to the optimization of stacking models. To solve these problems, we constructed a new feature set obtained from periodic tables for predicting the E_g and ΔH_f of halide double perovskites, and we further proposed a method integrating the nondominated sorting genetic algorithm (NSGA-II) and the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) decision-making tool for stacking model optimization to predict the E_g and ΔH_f of 540 compounds of halide double perovskites. Experimental results from 40 runs of 5-fold cross-validation demonstrate that our proposed new feature set enables ML models to achieve better performance than the original feature set. Moreover, the stacking model optimized by our proposed method yields better predicting performance than that of any individual single model and stacking regression models without optimization, with average improvements of 5.02%, 2.70%, 3.72% and 0.28% in MSE, RMSE, MAE and R², respectively, in E_g prediction, thus providing more effective guidance for screening potential compounds for solar cells from a large quantity of materials. Full article

This qualitative research investigates the adoption of Circular Economy (CE) principles in contemporary Australian architectural practice, referred to as circularity, to address climate change, resource scarcity, and increasing demands for built-environment resilience. The Australian government’s 2035 national circularity target, which aims to double 2024 levels, will have profound implications for architectural practice. This research examines the current and future ability of practices to adopt circularity. It addresses two specific knowledge gaps: (i) how circularity is currently being adopted by architectural practices in Australia, and (ii) what factors restrict or undermine this adoption. To address these gaps, the research draws on insights developed from focus groups and interviews (n = 33 participants) with professional Australian architectural service providers and closely related design and engineering practitioners. Qualitative data collection captured empirical evidence on the barriers, challenges, and opportunities for circularity, followed by NVivo-based Reflexive Thematic Analysis (RTA) that iteratively and inductively identified emerging themes. The findings indicate that architects’ and associated practitioners’ adoption of circularity in Australia is evident but constrained by short-term project horizons, fragmented responsibilities, limited procurement infrastructure, and uncertainty about material supply and skilled labour. The paper concludes that, despite some conceptual ambiguity and structural limitations in current practice models, adoption remains fragmented and selective and offers actions for architects and other stakeholders to address logistical infrastructure, regulatory frameworks, legal contracts, and barriers stemming from a short-term economic value mindset. Full article

Background and Objectives: Remimazolam and remifentanil are ultra-short-acting agents that are used for sedation and analgesia, respectively. Their combined effect on respiratory function is unclear. We evaluated whether co-administration produced dose-dependent respiratory depression and loss of consciousness (LOC) preceded oxygen desaturation. Materials and Methods: A randomized, double-blind trial was conducted from May to July 2024. Female patients (20–65 years; n = 108; American Society of Anesthesiologists physical status I–II) undergoing elective gynecological surgery were selected. Patients received remifentanil via target-controlled infusion (TCI) at effect-site concentrations (C_e) of 1.0, 1.5, or 2.0 ng/mL (Groups 1.0, 1.5, and 2.0) combined with a fixed C_e of 500 ng/mL remimazolam. Respiratory variables, timing of LOC, bispectral index, and adverse events were recorded. Results: Respiratory depression increased in a dose-dependent manner. Jaw thrust was required in 52.8% of Group 1.0 and 91.7% of Group 2.0 (p < 0.001). The need for 100% oxygen increased from 30.6% to 69.4% (p = 0.001). Minute ventilation decreased only in Group 2.0 (p = 0.008). Involuntary movements were frequent in Group 1.0 (p = 0.005). Conclusions: Remimazolam–remifentanil co-administration via TCI induced dose-dependent respiratory depression and pre-LOC desaturation. Therefore, continuous monitoring and careful titration are essential. Full article

The intense low-frequency magnetic field generated by the Electromagnetic Aircraft Launch System (EMALS) during operation poses a serious EMI threat to electronic equipment within carrier-based aircraft nacelles. To address this, a three-dimensional transient finite element model of a long-primary double-sided linear induction motor is established. Using a quasi-static equivalent method, the 118 Hz magnetic field distribution inside and outside a typical engine nacelle is characterized. Results indicate that due to the skin depth significantly exceeding material thickness, the eddy-current shielding of the aluminum alloy nacelle is inadequate, producing internal field intensities that far exceed standard limits and directly threaten sensitive onboard electronics. Based on the magnetic shunting principle, a composite shielding strategy is proposed: applying a flexible high-permeability coating on the nacelle surface to attenuate the overall field, supplemented by local permalloy shields for core equipment. Simulation verification demonstrates that this approach reduces the internal field to safe levels. It achieves effective shielding performance while balancing engineering feasibility with lightweight requirements, providing a viable pathway for ensuring the reliable protection of carrier-based aircraft in intense electromagnetic environments. Full article

Heritage rammed earth is a special soil material formed by manually selecting and ramming locally available Quaternary surface deposits layer by layer. However, the quantitative influence of material sourcing and rammed technology on the compressive properties of heritage rammed earth remains insufficiently understood, which limits the mechanical assessment and conservation planning of rammed earth sites. In this study, undisturbed rammed earth from 15 Ming Great Wall sites in Northwest China was investigated. Field 3D scanning, particle-size analysis, uniaxial compression testing, mesoscopic structural observation, and DEM analysis were combined to evaluate the effects of material characteristics and rammed technology on the compressive properties of heritage rammed earth. The results show clear regional differences in material characteristics and rammed technology parameters across the 15 sites. Across the five occurrence regions from the Extremely Arid Area to the Semi-Humid Area, dry density, silt fraction, curvature coefficient, and ramming pit distribution area ratio generally decreased, whereas clay and colloidal particle fraction, $d_{60}$, $C_u$, and rammed modulus generally increased. These variations were accompanied by changes in internal fabric, including aggregate proportion, coordination-number difference, high-stress particle proportion, and force-chain particle proportion. The peak stress and failure strain ranged from 0.48 to 1.01 MPa and from 0.03 to 0.07, respectively. Both parameters showed a decreasing regional trend from the extremely arid area to the semi-humid area, following the sequence: extremely arid area, arid area, semi-arid area, cold and humid area, and semi-humid area. From the Extremely Arid Area to the Semi-Humid Area, the shear failure mode changed from single-fork to mixed double-fork and then to intersecting double-fork. Regression analysis further showed that material and rammed technology parameters were closely related to mesoscopic structural parameters, with R² values generally greater than 0.75. These findings suggest that the regional differences in compressive behavior were closely associated with variations in material sourcing, rammed technology, internal fabric, and the load-bearing structure of rammed earth. Full article

Reversible emulsion drilling fluids integrate the advantages of water-based and oil-based systems, offering solutions to critical challenges in shale oil and gas development. However, conventional reversible emulsions face limitations including poor stability, high cost, and material scarcity. This research introduces widely available, eco-friendly modified nanocrystalline cellulose (MNCC) as a sustainable alternative. While current reversible drilling fluids primarily depend on organoclays and adopt aqueous phases containing 20–25% CaCl₂ for shale inhibition, pH-responsive MNCC was validated as an effective reversible emulsifier capable of stabilizing emulsions through 48 consecutive phase-inversion cycles. Enhanced emulsion stability was achieved with organoclay at an optimal dosage (≤2.5 g/100 mL), and a composite interfacial film superior to the film formed by pure MNCC was fabricated via the combination of organoclay and MNCC. Increasing the organoclay content elevated the acid requirements for phase inversion (due to its lipophilicity) but reduced the alkali needs. Finally, higher CaCl₂ concentrations in the aqueous phase reduced the acid demand for inversion yet increased alkali consumption and diminished stability in both oil-in-water (O/W) and water-in-oil (W/O) emulsions. These effects are attributed to the dual role of CaCl₂ in compressing the electrical double layer and modifying phase density differences, synergistically governing reversible inversion behavior. This research provides a foundation for applying nanocrystalline cellulose-stabilized reversible emulsion drilling fluids, offering practical solutions for efficient development of sensitive reservoirs like shale. Full article

Pumps, as critical equipment in water supply and drainage systems, contribute significantly to energy use and carbon emissions throughout their life cycle. This study quantified the life-cycle carbon footprint (LCF) of water supply and drainage pumps by developing a life-cycle assessment (LCA)-based model covering raw material acquisition, production and processing, transportation, operation, and recycling. Using the 400S-40 single-stage double-suction centrifugal pump as a case, the results showed that: (1) the total LCF of the pump was 5567.56 t CO₂e per unit; and (2) the operational stage accounted for 99.69% of the total life-cycle emissions. The findings indicate that, for the studied case, use-phase electricity consumption dominates the overall carbon footprint under the stated assumptions. Accordingly, for water utilities and pump users, improving operating efficiency and reducing avoidable electricity consumption are critical to carbon reduction. For pump manufacturers, enhancing processing technology, adopting low-carbon materials, improving durability, and promoting component-level maintenance and replacement can reduce embodied carbon and avoid unnecessary emissions associated with premature full-unit replacement. Beyond carbon reduction, these measures are also conducive to resource conservation, sustainable manufacturing, and the low-carbon transition of urban water infrastructure. Therefore, this study provides methodological support for the green design, operation, and management of pump equipment, and contributes to the sustainable development of water supply and drainage systems. Full article